<?php
    /**
     * This class provides a simple interface for OpenID (1.1 and 2.0) authentication.
     * Supports Yadis discovery.
     * The authentication process is stateless/dumb.
     *
     * Usage:
     * Sign-on with OpenID is a two step process:
     * Step one is authentication with the provider:
     * <code>
     * $openid = new LightOpenID('my-host.example.org');
     * $openid->identity = 'ID supplied by user';
     * header('Location: ' . $openid->authUrl());
     * </code>
     * The provider then sends various parameters via GET, one of them is openid_mode.
     * Step two is verification:
     * <code>
     * $openid = new LightOpenID('my-host.example.org');
     * if ($openid->mode) {
     *     echo $openid->validate() ? 'Logged in.' : 'Failed';
     * }
     * </code>
     *
     * Change the 'my-host.example.org' to your domain name. Do NOT use $_SERVER['HTTP_HOST']
     * for that, unless you know what you are doing.
     *
     * Optionally, you can set $returnUrl and $realm (or $trustRoot, which is an alias).
     * The default values for those are:
     * $openid->realm     = (!empty($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'];
     * $openid->returnUrl = $openid->realm . $_SERVER['REQUEST_URI'];
     * If you don't know their meaning, refer to any openid tutorial, or specification. Or just guess.
     *
     * AX and SREG extensions are supported.
     * To use them, specify $openid->required and/or $openid->optional before calling $openid->authUrl().
     * These are arrays, with values being AX schema paths (the 'path' part of the URL).
     * For example:
     *   $openid->required = array('namePerson/friendly', 'contact/email');
     *   $openid->optional = array('namePerson/first');
     * If the server supports only SREG or OpenID 1.1, these are automaticaly
     * mapped to SREG names, so that user doesn't have to know anything about the server.
     *
     * To get the values, use $openid->getAttributes().
     *
     *
     * The library requires PHP >= 5.1.2 with curl or http/https stream wrappers enabled.
     * @author Mewp
     * @copyright Copyright (c) 2010, Mewp
     * @license http://www.opensource.org/licenses/mit-license.php MIT
     */
    class Google_LightOpenID
    {
        public $returnUrl
             , $required = array()
             , $optional = array()
             , $verify_peer = null
             , $capath = null
             , $cainfo = null
             , $data;
        private $identity, $claimed_id;
        protected $server, $version, $trustRoot, $aliases, $identifier_select = false
                , $ax = false, $sreg = false, $setup_url = null, $headers = array();
        static protected $ax_to_sreg = array(
            'namePerson/friendly'     => 'nickname',
            'contact/email'           => 'email',
            'namePerson'              => 'fullname',
            'birthDate'               => 'dob',
            'person/gender'           => 'gender',
            'contact/postalCode/home' => 'postcode',
            'contact/country/home'    => 'country',
            'pref/language'           => 'language',
            'pref/timezone'           => 'timezone',
            );
    
        function __construct($host)
        {
            $this->trustRoot = (strpos($host, '://') ? $host : 'http://' . $host);
            if ((!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] != 'off')
                || (isset($_SERVER['HTTP_X_FORWARDED_PROTO'])
                && $_SERVER['HTTP_X_FORWARDED_PROTO'] == 'https')
            ) {
                $this->trustRoot = (strpos($host, '://') ? $host : 'https://' . $host);
            }
    
            if(($host_end = strpos($this->trustRoot, '/', 8)) !== false) {
                $this->trustRoot = substr($this->trustRoot, 0, $host_end);
            }
    
            $uri = rtrim(preg_replace('#((?<=\?)|&)openid\.[^&]+#', '', $_SERVER['REQUEST_URI']), '?');
            $this->returnUrl = $this->trustRoot . $uri;
    
            $this->data = ($_SERVER['REQUEST_METHOD'] === 'POST') ? $_POST : $_GET;
    
            if(!function_exists('curl_init') && !in_array('https', stream_get_wrappers())) {
                throw new ErrorException('You must have either https wrappers or curl enabled.');
            }
        }
    
        function __set($name, $value)
        {
            switch ($name) {
            case 'identity':
                if (strlen($value = trim((String) $value))) {
                    if (preg_match('#^xri:/*#i', $value, $m)) {
                        $value = substr($value, strlen($m[0]));
                    } elseif (!preg_match('/^(?:[=@+\$!\(]|https?:)/i', $value)) {
                        $value = "http://$value";
                    }
                    if (preg_match('#^https?://[^/]+$#i', $value, $m)) {
                        $value .= '/';
                    }
                }
                $this->$name = $this->claimed_id = $value;
                break;
            case 'trustRoot':
            case 'realm':
                $this->trustRoot = trim($value);
            }
        }
    
        function __get($name)
        {
            switch ($name) {
            case 'identity':
                # We return claimed_id instead of identity,
                # because the developer should see the claimed identifier,
                # i.e. what he set as identity, not the op-local identifier (which is what we verify)
                return $this->claimed_id;
            case 'trustRoot':
            case 'realm':
                return $this->trustRoot;
            case 'mode':
                return empty($this->data['openid_mode']) ? null : $this->data['openid_mode'];
            }
        }
    
        /**
         * Checks if the server specified in the url exists.
         *
         * @param $url url to check
         * @return true, if the server exists; false otherwise
         */
        function hostExists($url)
        {
            if (strpos($url, '/') === false) {
                $server = $url;
            } else {
                $server = @parse_url($url, PHP_URL_HOST);
            }
    
            if (!$server) {
                return false;
            }
    
            return !!gethostbynamel($server);
        }
    
        protected function request_curl($url, $method='GET', $params=array(), $update_claimed_id)
        {
            $params = http_build_query($params, '', '&');
            $curl = curl_init($url . ($method == 'GET' && $params ? '?' . $params : ''));
            curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
            curl_setopt($curl, CURLOPT_HEADER, false);
            curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
            curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
            curl_setopt($curl, CURLOPT_HTTPHEADER, array('Accept: application/xrds+xml, */*'));
    
            if($this->verify_peer !== null) {
                curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $this->verify_peer);
                if($this->capath) {
                    curl_setopt($curl, CURLOPT_CAPATH, $this->capath);
                }
    
                if($this->cainfo) {
                    curl_setopt($curl, CURLOPT_CAINFO, $this->cainfo);
                }
            }
    
            if ($method == 'POST') {
                curl_setopt($curl, CURLOPT_POST, true);
                curl_setopt($curl, CURLOPT_POSTFIELDS, $params);
            } elseif ($method == 'HEAD') {
                curl_setopt($curl, CURLOPT_HEADER, true);
                curl_setopt($curl, CURLOPT_NOBODY, true);
            } else {
                curl_setopt($curl, CURLOPT_HEADER, true);
                curl_setopt($curl, CURLOPT_HTTPGET, true);
            }
            $response = curl_exec($curl);
    
            if($method == 'HEAD' && curl_getinfo($curl, CURLINFO_HTTP_CODE) == 405) {
                curl_setopt($curl, CURLOPT_HTTPGET, true);
                $response = curl_exec($curl);
                $response = substr($response, 0, strpos($response, "\r\n\r\n"));
            }
    
            if($method == 'HEAD' || $method == 'GET') {
                $header_response = $response;
    
                # If it's a GET request, we want to only parse the header part.
                if($method == 'GET') {
                    $header_response = substr($response, 0, strpos($response, "\r\n\r\n"));
                }
    
                $headers = array();
                foreach(explode("\n", $header_response) as $header) {
                    $pos = strpos($header,':');
                    if ($pos !== false) {
                        $name = strtolower(trim(substr($header, 0, $pos)));
                        $headers[$name] = trim(substr($header, $pos+1));
                    }
                }
    
                if($update_claimed_id) {
                    # Updating claimed_id in case of redirections.
                    $effective_url = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL);
                    if($effective_url != $url) {
                        $this->identity = $this->claimed_id = $effective_url;
                    }
                }
    
                if($method == 'HEAD') {
                    return $headers;
                } else {
                    $this->headers = $headers;
                }
            }
    
            if (curl_errno($curl)) {
                throw new ErrorException(curl_error($curl), curl_errno($curl));
            }
    
            return $response;
        }
    
        protected function parse_header_array($array, $update_claimed_id)
        {
            $headers = array();
            foreach($array as $header) {
                $pos = strpos($header,':');
                if ($pos !== false) {
                    $name = strtolower(trim(substr($header, 0, $pos)));
                    $headers[$name] = trim(substr($header, $pos+1));
    
                    # Following possible redirections. The point is just to have
                    # claimed_id change with them, because the redirections
                    # are followed automatically.
                    # We ignore redirections with relative paths.
                    # If any known provider uses them, file a bug report.
                    if($name == 'location' && $update_claimed_id) {
                        if(strpos($headers[$name], 'http') === 0) {
                            $this->identity = $this->claimed_id = $headers[$name];
                        } elseif($headers[$name][0] == '/') {
                            $parsed_url = parse_url($this->claimed_id);
                            $this->identity =
                            $this->claimed_id = $parsed_url['scheme'] . '://'
                                              . $parsed_url['host']
                                              . $headers[$name];
                        }
                    }
                }
            }
            return $headers;
        }
    
        protected function request_streams($url, $method='GET', $params=array(), $update_claimed_id)
        {
            if(!$this->hostExists($url)) {
                throw new ErrorException("Could not connect to $url.", 404);
            }
    
            $params = http_build_query($params, '', '&');
            switch($method) {
            case 'GET':
                $opts = array(
                    'http' => array(
                        'method' => 'GET',
                        'header' => 'Accept: application/xrds+xml, */*',
                        'ignore_errors' => true,
                    ), 'ssl' => array(
                        'CN_match' => parse_url($url, PHP_URL_HOST),
                    ),
                );
                $url = $url . ($params ? '?' . $params : '');
                break;
            case 'POST':
                $opts = array(
                    'http' => array(
                        'method' => 'POST',
                        'header'  => 'Content-type: application/x-www-form-urlencoded',
                        'content' => $params,
                        'ignore_errors' => true,
                    ), 'ssl' => array(
                        'CN_match' => parse_url($url, PHP_URL_HOST),
                    ),
                );
                break;
            case 'HEAD':
                # We want to send a HEAD request,
                # but since get_headers doesn't accept $context parameter,
                # we have to change the defaults.
                $default = stream_context_get_options(stream_context_get_default());
                stream_context_get_default(
                    array(
                        'http' => array(
                            'method' => 'HEAD',
                            'header' => 'Accept: application/xrds+xml, */*',
                            'ignore_errors' => true,
                        ), 'ssl' => array(
                            'CN_match' => parse_url($url, PHP_URL_HOST),
                        ),
                    )
                );
    
                $url = $url . ($params ? '?' . $params : '');
                $headers = get_headers ($url);
                if(!$headers) {
                    return array();
                }
    
                if(intval(substr($headers[0], strlen('HTTP/1.1 '))) == 405) {
                    # The server doesn't support HEAD, so let's emulate it with
                    # a GET.
                    $args = func_get_args();
                    $args[1] = 'GET';
                    call_user_func_array(array($this, 'request_streams'), $args);
                    return $this->headers;
                }
    
                $headers = $this->parse_header_array($headers, $update_claimed_id);
    
                # And restore them.
                stream_context_get_default($default);
                return $headers;
            }
    
            if($this->verify_peer) {
                $opts['ssl'] += array(
                    'verify_peer' => true,
                    'capath'      => $this->capath,
                    'cafile'      => $this->cainfo,
                );
            }
    
            $context = stream_context_create ($opts);
            $data = file_get_contents($url, false, $context);
            # This is a hack for providers who don't support HEAD requests.
            # It just creates the headers array for the last request in $this->headers.
            if(isset($http_response_header)) {
                $this->headers = $this->parse_header_array($http_response_header, $update_claimed_id);
            }
    
            return file_get_contents($url, false, $context);
        }
    
        protected function request($url, $method='GET', $params=array(), $update_claimed_id=false)
        {
            if (function_exists('curl_init')
                && (!in_array('https', stream_get_wrappers()) || !ini_get('safe_mode') && !ini_get('open_basedir'))
            ) {
                return $this->request_curl($url, $method, $params, $update_claimed_id);
            }
            return $this->request_streams($url, $method, $params, $update_claimed_id);
        }
    
        protected function build_url($url, $parts)
        {
            if (isset($url['query'], $parts['query'])) {
                $parts['query'] = $url['query'] . '&' . $parts['query'];
            }
    
            $url = $parts + $url;
            $url = $url['scheme'] . '://'
                 . (empty($url['username'])?''
                     :(empty($url['password'])? "{$url['username']}@"
                     :"{$url['username']}:{$url['password']}@"))
                 . $url['host']
                 . (empty($url['port'])?'':":{$url['port']}")
                 . (empty($url['path'])?'':$url['path'])
                 . (empty($url['query'])?'':"?{$url['query']}")
                 . (empty($url['fragment'])?'':"#{$url['fragment']}");
            return $url;
        }
    
        /**
         * Helper function used to scan for <meta>/<link> tags and extract information
         * from them
         */
        protected function htmlTag($content, $tag, $attrName, $attrValue, $valueName)
        {
            preg_match_all("#<{$tag}[^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*$valueName=['\"](.+?)['\"][^>]*/?>#i", $content, $matches1);
            preg_match_all("#<{$tag}[^>]*$valueName=['\"](.+?)['\"][^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*/?>#i", $content, $matches2);
    
            $result = array_merge($matches1[1], $matches2[1]);
            return empty($result)?false:$result[0];
        }
    
        /**
         * Performs Yadis and HTML discovery. Normally not used.
         * @param $url Identity URL.
         * @return String OP Endpoint (i.e. OpenID provider address).
         * @throws ErrorException
         */
        function discover($url)
        {
            if (!$url) throw new ErrorException('No identity supplied.');
            # Use xri.net proxy to resolve i-name identities
            if (!preg_match('#^https?:#', $url)) {
                $url = "https://xri.net/$url";
            }
    
            # We save the original url in case of Yadis discovery failure.
            # It can happen when we'll be lead to an XRDS document
            # which does not have any OpenID2 services.
            $originalUrl = $url;
    
            # A flag to disable yadis discovery in case of failure in headers.
            $yadis = true;
    
            # We'll jump a maximum of 5 times, to avoid endless redirections.
            for ($i = 0; $i < 5; $i ++) {
                if ($yadis) {
                    $headers = $this->request($url, 'HEAD', array(), true);
    
                    $next = false;
                    if (isset($headers['x-xrds-location'])) {
                        $url = $this->build_url(parse_url($url), parse_url(trim($headers['x-xrds-location'])));
                        $next = true;
                    }
    
                    if (isset($headers['content-type'])
                        && (strpos($headers['content-type'], 'application/xrds+xml') !== false
                            || strpos($headers['content-type'], 'text/xml') !== false)
                    ) {
                        # Apparently, some providers return XRDS documents as text/html.
                        # While it is against the spec, allowing this here shouldn't break
                        # compatibility with anything.
                        # ---
                        # Found an XRDS document, now let's find the server, and optionally delegate.
                        $content = $this->request($url, 'GET');
    
                        preg_match_all('#<Service.*?>(.*?)</Service>#s', $content, $m);
                        foreach($m[1] as $content) {
                            $content = ' ' . $content; # The space is added, so that strpos doesn't return 0.
    
                            # OpenID 2
                            $ns = preg_quote('http://specs.openid.net/auth/2.0/', '#');
                            if(preg_match('#<Type>\s*'.$ns.'(server|signon)\s*</Type>#s', $content, $type)) {
                                if ($type[1] == 'server') $this->identifier_select = true;
    
                                preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
                                preg_match('#<(Local|Canonical)ID>(.*)</\1ID>#', $content, $delegate);
                                if (empty($server)) {
                                    return false;
                                }
                                # Does the server advertise support for either AX or SREG?
                                $this->ax   = (bool) strpos($content, '<Type>http://openid.net/srv/ax/1.0</Type>');
                                $this->sreg = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>')
                                           || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
    
                                $server = $server[1];
                                if (isset($delegate[2])) $this->identity = trim($delegate[2]);
                                $this->version = 2;
    
                                $this->server = $server;
                                return $server;
                            }
    
                            # OpenID 1.1
                            $ns = preg_quote('http://openid.net/signon/1.1', '#');
                            if (preg_match('#<Type>\s*'.$ns.'\s*</Type>#s', $content)) {
    
                                preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
                                preg_match('#<.*?Delegate>(.*)</.*?Delegate>#', $content, $delegate);
                                if (empty($server)) {
                                    return false;
                                }
                                # AX can be used only with OpenID 2.0, so checking only SREG
                                $this->sreg = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>')
                                           || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
    
                                $server = $server[1];
                                if (isset($delegate[1])) $this->identity = $delegate[1];
                                $this->version = 1;
    
                                $this->server = $server;
                                return $server;
                            }
                        }
    
                        $next = true;
                        $yadis = false;
                        $url = $originalUrl;
                        $content = null;
                        break;
                    }
                    if ($next) continue;
    
                    # There are no relevant information in headers, so we search the body.
                    $content = $this->request($url, 'GET', array(), true);
    
                    if (isset($this->headers['x-xrds-location'])) {
                        $url = $this->build_url(parse_url($url), parse_url(trim($this->headers['x-xrds-location'])));
                        continue;
                    }
    
                    $location = $this->htmlTag($content, 'meta', 'http-equiv', 'X-XRDS-Location', 'content');
                    if ($location) {
                        $url = $this->build_url(parse_url($url), parse_url($location));
                        continue;
                    }
                }
    
                if (!$content) $content = $this->request($url, 'GET');
    
                # At this point, the YADIS Discovery has failed, so we'll switch
                # to openid2 HTML discovery, then fallback to openid 1.1 discovery.
                $server   = $this->htmlTag($content, 'link', 'rel', 'openid2.provider', 'href');
                $delegate = $this->htmlTag($content, 'link', 'rel', 'openid2.local_id', 'href');
                $this->version = 2;
    
                if (!$server) {
                    # The same with openid 1.1
                    $server   = $this->htmlTag($content, 'link', 'rel', 'openid.server', 'href');
                    $delegate = $this->htmlTag($content, 'link', 'rel', 'openid.delegate', 'href');
                    $this->version = 1;
                }
    
                if ($server) {
                    # We found an OpenID2 OP Endpoint
                    if ($delegate) {
                        # We have also found an OP-Local ID.
                        $this->identity = $delegate;
                    }
                    $this->server = $server;
                    return $server;
                }
    
                throw new ErrorException("No OpenID Server found at $url", 404);
            }
            throw new ErrorException('Endless redirection!', 500);
        }
    
        protected function sregParams()
        {
            $params = array();
            # We always use SREG 1.1, even if the server is advertising only support for 1.0.
            # That's because it's fully backwards compatibile with 1.0, and some providers
            # advertise 1.0 even if they accept only 1.1. One such provider is myopenid.com
            $params['openid.ns.sreg'] = 'http://openid.net/extensions/sreg/1.1';
            if ($this->required) {
                $params['openid.sreg.required'] = array();
                foreach ($this->required as $required) {
                    if (!isset(self::$ax_to_sreg[$required])) continue;
                    $params['openid.sreg.required'][] = self::$ax_to_sreg[$required];
                }
                $params['openid.sreg.required'] = implode(',', $params['openid.sreg.required']);
            }
    
            if ($this->optional) {
                $params['openid.sreg.optional'] = array();
                foreach ($this->optional as $optional) {
                    if (!isset(self::$ax_to_sreg[$optional])) continue;
                    $params['openid.sreg.optional'][] = self::$ax_to_sreg[$optional];
                }
                $params['openid.sreg.optional'] = implode(',', $params['openid.sreg.optional']);
            }
            return $params;
        }
    
        protected function axParams()
        {
            $params = array();
            if ($this->required || $this->optional) {
                $params['openid.ns.ax'] = 'http://openid.net/srv/ax/1.0';
                $params['openid.ax.mode'] = 'fetch_request';
                $this->aliases  = array();
                $counts   = array();
                $required = array();
                $optional = array();
                foreach (array('required','optional') as $type) {
                    foreach ($this->$type as $alias => $field) {
                        if (is_int($alias)) $alias = strtr($field, '/', '_');
                        $this->aliases[$alias] = 'http://axschema.org/' . $field;
                        if (empty($counts[$alias])) $counts[$alias] = 0;
                        $counts[$alias] += 1;
                        ${$type}[] = $alias;
                    }
                }
                foreach ($this->aliases as $alias => $ns) {
                    $params['openid.ax.type.' . $alias] = $ns;
                }
                foreach ($counts as $alias => $count) {
                    if ($count == 1) continue;
                    $params['openid.ax.count.' . $alias] = $count;
                }
    
                # Don't send empty ax.requied and ax.if_available.
                # Google and possibly other providers refuse to support ax when one of these is empty.
                if($required) {
                    $params['openid.ax.required'] = implode(',', $required);
                }
                if($optional) {
                    $params['openid.ax.if_available'] = implode(',', $optional);
                }
            }
            return $params;
        }
    
        protected function authUrl_v1($immediate)
        {
            $returnUrl = $this->returnUrl;
            # If we have an openid.delegate that is different from our claimed id,
            # we need to somehow preserve the claimed id between requests.
            # The simplest way is to just send it along with the return_to url.
            if($this->identity != $this->claimed_id) {
                $returnUrl .= (strpos($returnUrl, '?') ? '&' : '?') . 'openid.claimed_id=' . $this->claimed_id;
            }
    
            $params = array(
                'openid.return_to'  => $returnUrl,
                'openid.mode'       => $immediate ? 'checkid_immediate' : 'checkid_setup',
                'openid.identity'   => $this->identity,
                'openid.trust_root' => $this->trustRoot,
                ) + $this->sregParams();
    
            return $this->build_url(parse_url($this->server)
                                   , array('query' => http_build_query($params, '', '&')));
        }
    
        protected function authUrl_v2($immediate)
        {
            $params = array(
                'openid.ns'          => 'http://specs.openid.net/auth/2.0',
                'openid.mode'        => $immediate ? 'checkid_immediate' : 'checkid_setup',
                'openid.return_to'   => $this->returnUrl,
                'openid.realm'       => $this->trustRoot,
            );
            if ($this->ax) {
                $params += $this->axParams();
            }
            if ($this->sreg) {
                $params += $this->sregParams();
            }
            if (!$this->ax && !$this->sreg) {
                # If OP doesn't advertise either SREG, nor AX, let's send them both
                # in worst case we don't get anything in return.
                $params += $this->axParams() + $this->sregParams();
            }
    
            if ($this->identifier_select) {
                $params['openid.identity'] = $params['openid.claimed_id']
                     = 'http://specs.openid.net/auth/2.0/identifier_select';
            } else {
                $params['openid.identity'] = $this->identity;
                $params['openid.claimed_id'] = $this->claimed_id;
            }
    
            return $this->build_url(parse_url($this->server)
                                   , array('query' => http_build_query($params, '', '&')));
        }
    
        /**
         * Returns authentication url. Usually, you want to redirect your user to it.
         * @return String The authentication url.
         * @param String $select_identifier Whether to request OP to select identity for an user in OpenID 2. Does not affect OpenID 1.
         * @throws ErrorException
         */
        function authUrl($immediate = false)
        {
            if ($this->setup_url && !$immediate) return $this->setup_url;
            if (!$this->server) $this->discover($this->identity);
    
            if ($this->version == 2) {
                return $this->authUrl_v2($immediate);
            }
            return $this->authUrl_v1($immediate);
        }
    
        /**
         * Performs OpenID verification with the OP.
         * @return Bool Whether the verification was successful.
         * @throws ErrorException
         */
        function validate()
        {
            # If the request was using immediate mode, a failure may be reported
            # by presenting user_setup_url (for 1.1) or reporting
            # mode 'setup_needed' (for 2.0). Also catching all modes other than
            # id_res, in order to avoid throwing errors.
            if(isset($this->data['openid_user_setup_url'])) {
                $this->setup_url = $this->data['openid_user_setup_url'];
                return false;
            }
            if($this->mode != 'id_res') {
                return false;
            }
    
            $this->claimed_id = isset($this->data['openid_claimed_id'])?$this->data['openid_claimed_id']:$this->data['openid_identity'];
            $params = array(
                'openid.assoc_handle' => $this->data['openid_assoc_handle'],
                'openid.signed'       => $this->data['openid_signed'],
                'openid.sig'          => $this->data['openid_sig'],
                );
    
            if (isset($this->data['openid_ns'])) {
                # We're dealing with an OpenID 2.0 server, so let's set an ns
                # Even though we should know location of the endpoint,
                # we still need to verify it by discovery, so $server is not set here
                $params['openid.ns'] = 'http://specs.openid.net/auth/2.0';
            } elseif (isset($this->data['openid_claimed_id'])
                && $this->data['openid_claimed_id'] != $this->data['openid_identity']
            ) {
                # If it's an OpenID 1 provider, and we've got claimed_id,
                # we have to append it to the returnUrl, like authUrl_v1 does.
                $this->returnUrl .= (strpos($this->returnUrl, '?') ? '&' : '?')
                                 .  'openid.claimed_id=' . $this->claimed_id;
            }
    
            if ($this->data['openid_return_to'] != $this->returnUrl) {
                # The return_to url must match the url of current request.
                # I'm assuing that noone will set the returnUrl to something that doesn't make sense.
                return false;
            }
    
            $server = $this->discover($this->claimed_id);
    
            foreach (explode(',', $this->data['openid_signed']) as $item) {
                # Checking whether magic_quotes_gpc is turned on, because
                # the function may fail if it is. For example, when fetching
                # AX namePerson, it might containg an apostrophe, which will be escaped.
                # In such case, validation would fail, since we'd send different data than OP
                # wants to verify. stripslashes() should solve that problem, but we can't
                # use it when magic_quotes is off.
                $value = $this->data['openid_' . str_replace('.','_',$item)];
                $params['openid.' . $item] = function_exists('get_magic_quotes_gpc') && get_magic_quotes_gpc() ? stripslashes($value) : $value;
    
            }
    
            $params['openid.mode'] = 'check_authentication';
    
            $response = $this->request($server, 'POST', $params);
    
            return preg_match('/is_valid\s*:\s*true/i', $response);
        }
    
        protected function getAxAttributes()
        {
            $alias = null;
            if (isset($this->data['openid_ns_ax'])
                && $this->data['openid_ns_ax'] != 'http://openid.net/srv/ax/1.0'
            ) { # It's the most likely case, so we'll check it before
                $alias = 'ax';
            } else {
                # 'ax' prefix is either undefined, or points to another extension,
                # so we search for another prefix
                foreach ($this->data as $key => $val) {
                    if (substr($key, 0, strlen('openid_ns_')) == 'openid_ns_'
                        && $val == 'http://openid.net/srv/ax/1.0'
                    ) {
                        $alias = substr($key, strlen('openid_ns_'));
                        break;
                    }
                }
            }
            if (!$alias) {
                # An alias for AX schema has not been found,
                # so there is no AX data in the OP's response
                return array();
            }
    
            $attributes = array();
            foreach (explode(',', $this->data['openid_signed']) as $key) {
                $keyMatch = $alias . '.value.';
                if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
                    continue;
                }
                $key = substr($key, strlen($keyMatch));
                if (!isset($this->data['openid_' . $alias . '_type_' . $key])) {
                    # OP is breaking the spec by returning a field without
                    # associated ns. This shouldn't happen, but it's better
                    # to check, than cause an E_NOTICE.
                    continue;
                }
                $value = $this->data['openid_' . $alias . '_value_' . $key];
                $key = substr($this->data['openid_' . $alias . '_type_' . $key],
                              strlen('http://axschema.org/'));
    
                $attributes[$key] = $value;
            }
            return $attributes;
        }
    
        protected function getSregAttributes()
        {
            $attributes = array();
            $sreg_to_ax = array_flip(self::$ax_to_sreg);
            foreach (explode(',', $this->data['openid_signed']) as $key) {
                $keyMatch = 'sreg.';
                if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
                    continue;
                }
                $key = substr($key, strlen($keyMatch));
                if (!isset($sreg_to_ax[$key])) {
                    # The field name isn't part of the SREG spec, so we ignore it.
                    continue;
                }
                $attributes[$sreg_to_ax[$key]] = $this->data['openid_sreg_' . $key];
            }
            return $attributes;
        }
    
        /**
         * Gets AX/SREG attributes provided by OP. should be used only after successful validaton.
         * Note that it does not guarantee that any of the required/optional parameters will be present,
         * or that there will be no other attributes besides those specified.
         * In other words. OP may provide whatever information it wants to.
         *     * SREG names will be mapped to AX names.
         *     * @return Array Array of attributes with keys being the AX schema names, e.g. 'contact/email'
         * @see http://www.axschema.org/types/
         */
        function getAttributes()
        {
            if (isset($this->data['openid_ns'])
                && $this->data['openid_ns'] == 'http://specs.openid.net/auth/2.0'
            ) { # OpenID 2.0
                # We search for both AX and SREG attributes, with AX taking precedence.
                return $this->getAxAttributes() + $this->getSregAttributes();
            }
            return $this->getSregAttributes();
        }
    }
